<template>
  <div class="score-case">
    <div class="table">
      <table>
        <thead>
          <tr>
            <th>编号</th>
            <th>科目</th>
            <th>成绩</th>
            <th>考试时间</th>
            <th>操作</th>
          </tr>
        </thead>
        <tbody>
          <!-- v-for渲染数据 分数<60变红 删除功能 修改时间格式-->
          <tr v-for="item in list" :key="item.id">
            <td>{{item.id}}</td>
            <td>{{item.subject}}</td>
            <td :class="item.score > 60?'':'red'">{{item.score}}</td>
            <td>{{formatDate(item.date)}}</td>
            <td><a href="#" @click.prevent="del(item.id)">删除</a></td> 
          </tr>
          <!-- <tr >
            <td>1</td>
            <td>语文</td>
            <td class="red">56</td>
            <td>Tue Jun 07 2022 10:00:00 GMT+0800 (中国标准时间)</td>
            <td><a href="#">删除</a></td>
          </tr>
          <tr >
            <td>2</td>
            <td>数学</td>
            <td>100</td>
            <td>Tue Jun 07 2022 10:00:00 GMT+0800 (中国标准时间)</td>
            <td><a href="#">删除</a></td>
          </tr> -->
        </tbody>
        <!-- list为空时展示该模块 -->
        <tbody v-show="list.length===0">
          <tr>
            <td colspan="5">
              <span class="none">暂无数据</span>
            </td>
          </tr>
        </tbody>
        <!-- list不为空时展示该模块 -->
        <tfoot v-show="list.length>0">
          <tr>
            <td colspan="5">
              <span>总分：{{sum}}</span>
              <span style="margin-left:50px">平均分：{{avg}}</span>
            </td>
          </tr>
        </tfoot>
      </table>
    </div>
    <div class="form">
      <div class="form-item">
        <div class="label">科目：</div>
        <div class="input">
          <!-- 科目去空格 -->
          <input type="text" placeholder="请输入科目" v-model.trim="subject" />
        </div>
      </div>
      <div class="form-item">
        <div class="label">分数：</div>
        <div class="input">
          <!-- 分数转为数字类型 -->
          <input type="text" placeholder="请输入分数" v-model.number="score" />
        </div>
      </div>
      <div class="form-item">
        <div class="label"></div>
        <div class="input">
          <button class="submit" @click="addFn" >添加</button>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
// 引入moment模块
import moment from 'moment'
// import { filter } from 'vue/types/umd';
export default {
  name: 'ScoreCase',
  data () {
    return {
      // 删完的时候list=[] =>不会报错
      list: JSON.parse(localStorage.getItem('scoreList')) || [],
      subject: '',
      score: ''
    }
  },
  // 计算总分和平均分
  computed:{
    sum() {
      return this.list.reduce((prev,item)=> prev+=item.score ,0)
    },
    avg() {
      return this.list.length ? (this.sum/this.list.length).toFixed(2) : 0
    }
  },
  // 监听属性 list发生变化保存到本地
  watch:{
    // 监听属性的完整写法(是一个对象)
    list:{
      deep: true,       //deep代表深度监听，可以监听到对象内部的变化
      handler() {
        localStorage.setItem('scoreList',JSON.stringify(this.list))
      }
    }
  },
  methods:{
    del(id) { //删除功能
      // filter过滤不符合条件的
      this.list = this.list.filter(item=>item.id !==id)
    },
    // 添加功能
    addFn() {
      if(this.subject && this.score>=0 && this.score<=100 && this.score!=='' ) {
        this.list.push({
        id : this.list.length>0 ? this.list.at(-1).id+1 :1,
        subject : this.subject,
        score : this.score,
        date : new Date()
      })
      // 添加完后清空表单内容
      this.subject = '',
      this.score =''
      }else{
        alert('输入信息错误')
      } 
    },
    formatDate(time) {
      return moment(time).format('YYYY-MM-DD HH:mm:ss')
    }
  }
};
</script>

<style lang="less">
.score-case {
  width: 1000px;
  margin: 50px auto;
  display: flex;
  .table {
    flex: 4;
    table {
      width: 100%;
      border-spacing: 0;
      border-top: 1px solid #ccc;
      border-left: 1px solid #ccc;
      th {
        background: #f5f5f5;
      }
      tr:hover td {
        background: #f5f5f5;
      }
      td,
      th {
        border-bottom: 1px solid #ccc;
        border-right: 1px solid #ccc;
        text-align: center;
        padding: 10px;
        &.red {
          color: red;
        }
      }
    }
    .none {
      height: 100px;
      line-height: 100px;
      color: #999;
    }
  }
  .form {
    flex: 1;
    padding: 20px;
    .form-item {
      display: flex;
      margin-bottom: 20px;
      align-items: center;
    }
    .form-item .label {
      width: 60px;
      text-align: right;
      font-size: 14px;
    }
    .form-item .input {
      flex: 1;
    }
    .form-item input,
    .form-item select {
      appearance: none;
      outline: none;
      border: 1px solid #ccc;
      width: 200px;
      height: 40px;
      box-sizing: border-box;
      padding: 10px;
      color: #666;
    }
    .form-item input::placeholder {
      color: #666;
    }
    .form-item .cancel,
    .form-item .submit {
      appearance: none;
      outline: none;
      border: 1px solid #ccc;
      border-radius: 4px;
      padding: 4px 10px;
      margin-right: 10px;
      font-size: 12px;
      background: #ccc;
    }
    .form-item .submit {
      border-color: #069;
      background: #069;
      color: #fff;
    }
  }
}
</style>